From: Guus Sliepen <guus@meshlink.io>
Date: Fri, 8 Aug 2014 09:59:39 +0000 (+0200)
Subject: Handle io_t's being deleted out of order while going through loop->ios.
X-Git-Url: https://git.meshlink.io/?a=commitdiff_plain;h=77c25aa7e676e4eb8c099940ca8c4b872b64415c;p=meshlink

Handle io_t's being deleted out of order while going through loop->ios.
---

diff --git a/src/event.c b/src/event.c
index d1a0e256..b6def622 100644
--- a/src/event.c
+++ b/src/event.c
@@ -81,6 +81,8 @@ void io_del(event_loop_t *loop, io_t *io) {
 	if(!io->cb)
 		return;
 
+	loop->deletion = true;
+
 	io_set(loop, io, 0);
 
 	splay_unlink_node(&loop->ios, &io->node);
@@ -115,6 +117,8 @@ void timeout_del(event_loop_t *loop, timeout_t *timeout) {
 	if(!timeout->cb)
 		return;
 
+	loop->deletion = true;
+
 	splay_unlink_node(&loop->timeouts, &timeout->node);
 	timeout->cb = 0;
 	timeout->tv = (struct timeval){0, 0};
@@ -167,6 +171,8 @@ void signal_del(event_loop_t *loop, signal_t *sig) {
 	if(!sig->cb)
 		return;
 
+	loop->deletion = true;
+
 	splay_unlink_node(&loop->signals, &sig->node);
 	sig->cb = NULL;
 }
@@ -217,11 +223,21 @@ bool event_loop_run(event_loop_t *loop) {
 		if(!n)
 			continue;
 
+		// Normally, splay_each allows the current node to be deleted. However,
+		// it can be that one io callback triggers the deletion of another io,
+		// so we have to detect this and break the loop.
+
+		loop->deletion = false;
+
 		for splay_each(io_t, io, &loop->ios) {
-			if(FD_ISSET(io->fd, &writable))
+			if(FD_ISSET(io->fd, &writable) && io->cb)
 				io->cb(loop, io->data, IO_WRITE);
-			else if(FD_ISSET(io->fd, &readable))
+			if(loop->deletion)
+				break;
+			if(FD_ISSET(io->fd, &readable) && io->cb)
 				io->cb(loop, io->data, IO_READ);
+			if(loop->deletion)
+				break;
 		}
 	}
 
diff --git a/src/event.h b/src/event.h
index c90e5067..6e77fbdf 100644
--- a/src/event.h
+++ b/src/event.h
@@ -60,6 +60,7 @@ struct event_loop_t {
 
 	volatile bool running;
 	struct timeval now;
+	bool deletion;
 	
 	splay_tree_t ios;
 	splay_tree_t timeouts;